3. SYSTEMS DESIGN

3.2 COMMERCIAL INSTALLATIONS

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Insulation in commercial buildings such as schools, shopping centers, warehouses, hospitals, hotels and other public buildings is designed primarily to reduce energy consumption and/or prevent condensation. The types of mechanical systems commonly insulated in commercial installations vary only slightly from project to project, and involve a relatively narrow temperature range. Typical mechanical systems include:

1. Plumbing (13°C to 80°C)

2. Ducts and housings (15°C to 43°C)

3. Steam and condensate (100°C to 185°C) *upper limit will vary with the pressure of steam

4. Outdoor air intake (seasonal outdoors temperature range)

5. Roof drains (1°C to 15°C)

6. Hot water heating (80°C to 100°C)

7. Chilled water (5°C to 13°C)

8. Engine exhaust (approximately 675°C)

9. Kitchen exhaust ducts (approximately 1100°C)

10. Refrigerant suction (–40°C to 10°C)

Care should be taken in designing commercial insulation systems to specify the thickness, material and finish necessary to accomplish the purpose of the application. Commercial buildings are designed to accommodate either human comfort or materials storage. Generally these purposes are achieved through the proper design of the heating/ventilating/cooling and plumbing systems. The purpose of the insulation system design is to enhance the efficiency of these systems, reduce energy consumption, help prevent damage from condensation, improve sound control and prevent fire.

3.2.1 DESIGN OBJECTIVES

The insulation system designer must be aware of the objectives of the installation and the amount and type of equipment planned to achieve these objectives. In some cases, as with steam heating, proper insulation planning can reduce the required capacity of the generating system. In the case of fruit and vegetable or refrigerated meat storage, temperature maintenance and condensation control objectives will supersede economic thickness design. Appearance and hygiene factors can also affect the choice of finishes in exposed areas and/or areas where food is being prepared or stored.

Condensation control on ducts, chillers, roof drains and cold piping is a basic function of insulation in commercial buildings. Design objectives here are to choose materials and application methods which will achieve the best vapour retarder seal possible, and to calculate the thickness of insulation necessary to prevent condensation.

Insulation chosen for personnel protection and/or fire protection must be able to withstand high temperatures without contributing to a possible fire hazard. Engine exhausts which can reach temperatures of 455°C to 675°C should be insulated sufficiently to reduce surface temperatures exposed to personnel or flammable materials to under 60°C. Kitchen exhaust ducts which are subjected to flammable grease accumulation fall within the same design criteria.

3.2.2 MATERIALS

The insulation materials most widely used on commercial installations are:

1. Glass and Mineral Fiber (pipe insulation, flexible blanket and board):

– available with various jacketing materials

– accommodates general commercial temperature range

– meet code requirement for flame spread and smoke developed

2. Elastomeric (pipe covering and sheets):

– no additional vapour retarder or finish usually required

– used on plumbing piping, chilled water piping, suction piping, flexible lines and cold surfaces

– check manufacturers data for flame and smoke developed

3. Calcium Silicate (pipe covering and block):

– necessary for higher temperature commercial and industrial installations needing high compressive strength such as high pressure steam, diesel exhaust, kitchen exhaust and breechings

4. Urethane, Polisocyanurate, Phenolic Foam (blocks and pipe covering):

- necessary where a denser, less absorbent material is required

- accommodates the general commercial temperature range

- check code requirements for flame spread & smoke developed

5. Perlite (pipe covering and block):

- necessary for higher temperature commercial and industrial installations needing high compressive strength such as high pressure steam, diesel exhaust, kitchen exhaust and breeching.

- lightweight

- moisture resistant to 315°C

A variety of weather and vapour retarder jackets and mastics is available to aid insulation materials in meeting and designing objectives such as fire safety, appearance and system abuse protection.

3.2.3 SPECIFICATIONS

Because commercial installations involve relatively limited materials and applications choices, with few variations to the mechanical systems receiving insulation treatment, there is a tendency to prepare general specifications which are often insufficient for proper installation or bidding. For example, a specification which states that "chillers or all cold surfaces of chillers will be insulated..." can be interpreted several ways especially if it hasn't been designated as to whether or not the chiller has been factory insulated.

All materials, thicknesses, finishes, securements and design objectives should be carefully communicated to the insulation contractor.